—Must I turn off the gas after cooking ?--Of course . You can never be careful with that.

问题补充：

—Must I turn off the gas after cooking ?

--Of course . You can never be careful with that.

A. enough

B. too

C. so

D. very

答案：

A. enough

(答案→)B. too

C. so

D. very

解析：can / could not...too是一个固定搭配，表示“无论怎样也不过分；此句话的汉语意思是：－做完饭后一定要把煤气关掉吗？－当然，你越小心越好。有些学生误认为can never be too…是一个孤立的结构，而逐字翻译，从而误选D。